Early View e202512119
Research Article

Plasma-Engineered Sub-10 nm Surface Fluorination Enables Ultraselective Hollow Fiber Membranes

Can Wang

Can Wang

School of Rare Earths, University of Science and Technology of China, Hefei, 230026 China

School of Chemistry and Chemical Engineering, Heze University, Heze, 274015 China

CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Solid State Battery and Energy Storage Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190 China

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Xiaobo Chen

Xiaobo Chen

CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Solid State Battery and Energy Storage Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190 China

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Xing Liu

Xing Liu

CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Solid State Battery and Energy Storage Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190 China

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Zhenyuan Li

Zhenyuan Li

CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Solid State Battery and Energy Storage Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190 China

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Prof. Ruixia Liu

Prof. Ruixia Liu

CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Solid State Battery and Energy Storage Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190 China

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Prof. Shuangjiang Luo

Corresponding Author

Prof. Shuangjiang Luo

CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Solid State Battery and Energy Storage Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190 China

E-mail: [email protected], [email protected]

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Prof. Suojiang Zhang

Corresponding Author

Prof. Suojiang Zhang

CAS Key Laboratory of Green Process and Engineering, Beijing Key Laboratory of Solid State Battery and Energy Storage Process, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190 China

Henan University, Zhengzhou, 450046 China

E-mail: [email protected], [email protected]

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First published: 23 July 2025

Graphical Abstract

Surface fluorination of PDMS-coated hollow fiber membranes via CF4 plasma engineering achieves sub-10 nm nanoscale modification, simultaneously enhancing chain rigidity and narrowing pore size distribution. The optimized membrane demonstrates record gas separation performance with industrial-scale stability, surpassing the 2019 perfluoropolymer upper bounds and conventional polymeric hollow fiber membranes.

Abstract

While polymeric hollow fiber membranes (HFMs) offer scalable solutions for gas separations, their performance is fundamentally limited by the permeance-selectivity tradeoff and imprecise microporosity regulation. Herein, we propose a surface fluorination strategy using carbon tetrafluoride (CF4) plasma to engineer a sub-10 nm fluorinated and crosslinked layer on polydimethylsiloxane (PDMS)-coated Matrimid® HFMs. Through precise modulation of plasma parameters, we achieved controlled substitution of PDMS methyl groups/methyl hydrogen atoms with fluorine species (up to 27.7 mol% F content), 5.3-fold enhanced chain rigidity via fluorine-induced interchain interactions and steric hindrance, as well as narrowed pore size distribution with preferential ultra-micropore filling. The optimized HFM-50W-65Pa-500s membrane exhibits record-breaking He/N2 and He/CH4 selectivities of 1202 ± 13 and 1790 ± 12 with 170 ± 2 GPU He permeance, surpassing perfluoropolymer upper bounds and outperforming previously reported polymeric HFMs. Remarkably, it demonstrates molecular discrimination precision (α(He/CO2) = 56 ± 2.2, α(He/H2) = 4.1 ± 0.2) for pure-gas and attractive ternary He/(CO2+CH4) selectivity of 1005 ± 20 under 40-bar mixed-gas conditions while maintaining 720-h operational stability. This plasma-engineered fluorination paradigm combines nanoscale precision with industrial scalability, opening new avenues for advanced membrane design.

Conflict of Interests

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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